Jotco 10 Gallon Tall Tank Topper 20.5" Long Turns any 10 Gallon Tank into a Pet Mansion!! Dimensions are 20.5" x 11" x 18" Suitable for Hamsters, Gerbils, Degus, Rats and other similar size pets. All Jotco Tank Toppers come fully assembled with no extra steps. Just let down the ramp and set it on your tank!